Zn Es Zn-Sn galvanbevonatok korroziojanak osszehasonlito vizsgalata elektrokemiai impedanciaspektroszkopiai modszerrel

Translated title of the contribution: A comparative corrosion study of zinc and zinc-tin galvanic coatings by method of electrochemical impedance spectroscopy

Laura Sziráki, Zsuzsanna Pilbáth, Ágnes Cziráki

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Corrosion rates of electrodeposited Zn and Zn-Sn (20-30m%) coatings are compared to hot dipped ones and pure Zn is aerated/deaerated 0,5 mol.dm-3 sodium sulphate solution. Results of electrochemical impedance measurements performed on Zn-Sn coating deposited from a slightly acidic bath containing sulphate ions have revealed the merit ot the passivity of this alloy. Corrosion potential of the alloy remains close to that of pure Zn, while a compact non-stoichiometric Zn/ZnO and Sn/SnO/SnO2 layer forms and due to its weakly degenerated n-type semiconductance the rate of the cathodic processes are markedly reduced. From dependence of capacity on electrode potential the electron density in the oxide film (1019-1020 cm-3) was determined. The zinc oxide films are more sensitive to local damage in the presence of sulphate ions. The dark yellow chromate layer on Zn-Sn coating has better corrosion protection than the iridescent yellow chromate layer on Zn coating.

Translated title of the contributionA comparative corrosion study of zinc and zinc-tin galvanic coatings by method of electrochemical impedance spectroscopy
Original languageHungarian
Pages (from-to)43-49
Number of pages7
JournalKorrozios Figyelo
Volume40
Issue number2
Publication statusPublished - Jan 1 2000

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Surfaces, Coatings and Films
  • Materials Chemistry

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